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Topic: Cat 3126 to 3126 B or E (Read 4010 times)

Does anyone know if a 3126 B or E swamp in place of a 3126. I know the later engines have a 70 pin harness, rather then a 40 pin. But there are adapters for this.Just curious if anyone has actually performed this swap.

Caterpillar holders their cards tight to their chest, can't seem to get this info any where on the internet.

The caterpillar 3126 A model has a 40 pin connector, caterpillar 3126 B & E engines have a 70 pin connector to ECM.No there not a adapter that can be bought or used between the 40 pin and 70 pin connector. also note there is a lot of interesting You Tube video on how to bullet proof your Caterpillar engine. Going deep into subject, this is not happening other than Someone that’s wants to market for profit to make people think there is a problem. There is no information or has there been anyproblems within Caterpillar service system technical bulletins to back problems with there engines.

Would there be a need for an adapter if you swap engines and keep the ECM with its engine and supply the necessary power and grounds, the only reason I can think of if there is a problem with which data buss is available on the transplant engine and the intended recipient. Cat used CDL, j1708, and j1939. The recipient vehicle would need a compatible buss so the trans controller, abs if equipped, and other modules can still communicate.

Basically person can connect just about anything but first let everyone understand what each pin does in the ECM for Caterpillar 3126 A model 40 Pin data cable connector ( let let the wisdom explain what each pin does ) answer is clearly marked.

Next Caterpillar 3126 B & E models with the 70 pin data cable connector, and again your now working with more pins and more technical information ( the ECM clearly spells out what each pin does for the Caterpillar 3126 B & E engines.)

Next part to answering wisdom versus technical information the ,engine ECM is not the same and valuesto many data pins is not present. I stand by my post.

Gentleman, sometime aftermarket parts wisdom in some people’s minds a means to save money. Yes there is a gizmo made for just about everything but in a experience technician view point many problems about to come into play. Really have missed a point about above post, some place someone forgot to mention about the engine ECM which has programmed values only available to Caterpillar.

What this means connections of wiring adapter to adapt different engines with Caterpillar ECM that programmed for values to different engine S/N numbers and test assigned Engine Arrangement Number is not going to happen. Caterpillar ECM Information program has many factory pass word code that allow different programs that only Caterpillar Service tool ET can unlock. Basic my advice to the non-trained do it yourself mechanic the aftermarket wire adapter is available and cost lot of money Caterpillar has safe guards inplace that will not allow engine ECM to operate correct.

The only way a person change out a used electronic engine for example Cat C-9 with a Serial Number of 9DG 03162 with another 9DG Number real close . The arrangement number is where the engine build to certain specs come into play and that is where things go south to these aftermarket products. This subject goes a lot deeper and information is only available from Caterpillar and not to public.

Caterpillar built in a safe guard into aftermarket modified prevent tampering with engine and that is the ECM.

Thank you both for taking the time to explain this more clearly. It does fall in line with lots I have read. I would imagine I have more then 100 hours researching this.Some have done this, switching computers, some have done it, and the dash didn't work. But this was on trucks.I was told the extra wires on a 70 pin, are for more data info to the dash. Cat can take care of all that, if you have deep pockets.I plan to keep them out of the loop as much as possible.

Next question is, will a 8.3 Cummings bolt to the trans and converter (same pattern). Per a friend, Foretravel did not reinvent the wheel to put a Cat in these coaches. I do plan to call James Triana at Foretravel. I have a retired diesel mechanic helping me, and low voltage wiring is not issue for me. I can deal with that.

We have already replaced the injector O rings, cleaning the seats. Replaced one injector that I am not sure was bad. I had done a pyro test, and that cylinder was 100 degree's colder on warm up.Seats weren't bad,minor carbon, but the O rings were 1/2 gone.It ran fine for a few days, but still burning 1 qt per 100 - miles. Cat did a blow by test, said I have a hole out. But we pressure tested each cylinder with all the valves closed (rockers out). They all seemed equal.Now after a few days, went to start it, and I can barely get it started. Smells flooded,raw fuel, run's like it's on 3 cylinders. It's not cold out.Once it clears out, it's fine.But still have the oil consumption issue.

I want to abandon the whole engine I have. Everything, computer, pump everything. I have found several complete low mile used engines, with same 1WMXXXX serial number (40 pin).Sounds like unless I can swamp to a Cummings, that would be the easiest route to take.I don't want to get into fixing or rebuilding this engine, because unless one is willing to buy a $500.00 manual ($350.00 used), there isn't much info out there. It took a friend at Cat, to just get the valve lash. That was even hard for him to get!Thanks Chris

Yes, your coach is one of the heavier ones on the 3126 which is 7.2 liters.

James should be able to tell you want is involved in changing to the Cummins 8.3 liter. Like using different spec Caterpillar engines in your coach, this could become really involved.

Accessory mounting likely to be different. Cooling system the same capacity and same controls?Transmission ECU would need to be reprogrammed, as the Cummins, being longer stroke, will have a lower RPM operating range.

Indeed, brainstorm with James Triana at the Foretavel factory.

Guess my thought is, particularly if ready to scrap the engine, pull the head off and see what you have. If a scored cylinder/bad piston, I was at Mustang Caterpillar in Houston years ago when they had an outside firm do an in-frame bore and sleeve insert in a 3126.

Thanks Bret, no one in this area does that (mobile boring). Crossed that one of the list a few weeks ago. Taking it apart has been a thought, but don't want it non-mobile. Especially apart in some one else's shop $$$$.Bad enough in mine.It still has something else going on, like HEUI or ECM. Certainly don't want to throw parts at it guessing.Code only while warming up, then goes away. ID 164 FMI 11 N1 (injector activator pressure)Which is:Bad injectorBad injector O ringsBad sensorBad HEUIBad ECMThe 1st 3 have been covered, the fact I can drive it, and silverleaf shows good fuel pressure (within spec)Unfortunately no one has software to look at ECM deeper, and Cat didn't do it when I took it in, telling them about the code. They just did a blow by test, said you need a new motor, have a dead hole. I did get my money back from them, they agreed they dropped the ball.So from Cat work order:Blow by at Idle: 286 cu FT/HRMed idle 347.1 cu FT/HRSpec is 315 cu FT/HR at high idle under load...Min blow by is 160 cu FT/HRI read double the HP, so a 300 HP would be 600 cu FT/HRNever the less, has lots of blow by blue smoke out slobber tube (no oil, clean as a whistle), none out exhaust.Thanks Chris

gracerace, reading your post on all the work you have done on your engine troubleshooting.First of all engine blow by can come from another area other than the rings. Look at the turbocharger real close, first a bad seal in the turbocharger will produce excess blow by and oilusage as you stated. What you first indicated what you replaced injector o-rings, than your silver leaf code 164-11 Injection Actuation Pressure Fault. Did you preform the work yourself.The Code 164-11 can be cause from several problems. and replacement of one injector isleading to another area of problems. Incorrect voltage to injector itself which will not fire the Injector correct or not fire the injector all ( we have experienced several motorhome owners )that changed out injectors to fined out the injector was ok. The point want to make really donot think by what you have indicated your engine is bad. another area Injector Actuation Pressure Regulator sticking or bad. Note your engine does not have a injection pump or injector push rods and the only way your injectors will work is the high pressure engine oil that operates the injector. Will sometimes produce. Code of 42-11 or 164-11. I can keep goingdeeper and can provide technical Information from Caterpillar Service Information System.Will advise to rebuild your engine using many parts off your engine will run $ 30,000. Plusmany extras. Again if you can provide a step by step where you are at and where did youstart need complete engine serial number. Ask Dave, Dave Atherton Retired Cat Mechanic

Thank you DaveYour the 1st person I have talked to, that is giving me sound advice. I find it hard to believe, this engine went bad just like that. It has 118K miles.I bought it from a retired grape grower in Lodi Calif. with 112K miles. He has multiple tractors and a shop. he took good care of it, and drove it easy. He owned it most of the last 50K miles.He upgraded to a newer coach, because he wanted slides. I bought it, drove it home 1+K milles, no issues, no oil use. Drove it a few hundred miles around home, no issues, then another 2K miles down to Arizona year before last, no oil use.Driving home from Arizona,It started throwing a low boost code.

Got home,the manifold gasket was blown, so we pulled it off, I had it resurfaced, problem solved.While I had the turbo off, decided to have it freshened, just because it was off. It looked fine.At that point the waste gate was cracked, so I got a complete rebuilt turbo (not Chinese) from a reliable dealer in Spokane, Spokane pump. Been around since the 40's.Serviced the whole coach (every fluid), changed the oil and filter twice in 2K miles. I am just that way.When we got to California this year, at about 1K miles, it used 4-5 qts oil. Slobber tube is clean as a whistle, exhaust pipe clean, no smoke. Just bad blue smoke out the blow by tube, dip stick, and oil fill tube. I bought 4 cases of oil, and made sure it was full, drove about 1500 miles back home. Used 27 qts oil. never got lower then add line.I drive it very easy, 1700 RPM'sI read about the O rings and oil consumption, so decided to try those.While doing the injector O rings, we checked the charge cooler tube's for oil. Minor oil at the turbo, none down the pipes. Called Spokane pump, they said that is normal.Really was minor at the fins.Tried to have the injectors checked, but no one does them locally, they wanted to send them out.Seeing the O rings so bad, and the fact the engine was running smooth, had no reason to believe the injectors were bad. I replaced the one with the correct reman Cat part number, because on warm up, one cylinder was running 100 degree's colder. I had already received the injector, so I put it in just guessing.It seemed to run better, fuel now smelled like fresh burning fuel. The O rings were cracked and missing pieces.Replaced with Cat O rings.But still 1 qt oil every 100- miles.Then the second day, started hard, running on what sounds like 3 cyl. Once cleaned out, it seems to run fine, but smoke seems worse.Yes, did the work with my friend who is a retired diesel mechanic. We are both drag racers, and have built many gas engines.My friend is pretty knowledgeable with diesels, but not specifically with Cats, but has worked on them. But has done this type of work (O rings) on other brands.I personally was a Foretravel tech, did all the service on theses coach's. But we did not do major engine/trans work.The motor is a 1996 early 97 Foretravel coach.(on valve cover) 300 HP 3126 serial number 1WM03813Thank you so much for your time. This has been a bummer, as we bough the coach to have a bullet proof chassis. The engine was suppose to be my least worry.Chris

One of the thing I believe in is doing and oil sample very other year as a precaution and to help pinpoint if there are problems starting. Regarding excessive oil consumption I would also do a fuel sample analysis to see if oil may still be getting into the fuel and thinning out. Beside the areas of concern already mentioned were the injector cups cleaned and inspected for damage before installing the injectors. Was the proper grade and viscosity of the oil used in the oil change and calibration of the dip stick.Blowby can also be caused by worn valve guides.

So here is an update to our Kitty Cat issueSo down to the nitty gritty. The Caterpillar 3126 2 valve engine was a one year only motor in 1996/1997. They had a tendency to break piston rings. Many were fixed under warranty back when they were new.That is what happened to our motor. At 115K, it broke # 6 oil ring.It scared the cylinder wall so bad, it was beyond repair. May have been this way for a while, but just got worse. Who knows.So out comes the block to get sleeved. Sad, because the motor is perfect inside. Looks brand new. No codes, no loss of HP, no loss of boost. Just smoke and oil consumption.The head also had a minor crack, but wasn't causing any issue. So, rebuilt turbo, new rings,rod bearings one new piston skirt (they are 2 piece) and a good donor head which was rebuilt. We will now be as good as new (or better). Also replacing all the hoses, coolant & belts.I am a freak when it comes to engine detail, so every part has been cleaned and painted. More news and pictures later when she is back together running.

For sure Brett.My engine hoist would work, it's 1200 LBS. But renting a fork lift to put it back in, completely assembled. Just seems more stable.Will save all the work going in and out of the coach. Which actually we didn't do much of that.Most everything was easy to reach.Hope I can remember where all the hoses go...LOL....I marked a few before I took them off.

Update:Ready to install.......All in with new hose, coolant and belts. Under $3500.00Machine work, rebuilt head,sleeve installed, decked, honed and light hot tank $1890.00. This price included a $500.00 core charge for the cracked head replacement.Rings, one piston skirt,rod bearing and gaskets was about $1300.00 from Caterpillar, the rest was paint,oil, coolant, hose and misc.The turbo was already a fresh rebuild with 200 miles on it.

Point very well said total cost for parts and your labor $ 3,500.This is not a suprise onmy part but this past 2 years, I have been involved in on 10 Cat engines 3126 to C-9complete engine repair using mix and match of usable parts on engine that failed. Whatthe above engines out the door repair $ 28, 500 to $ 33,000 dollars. These numbers areVery inflated and only getting higher as time moves on for a reman or rebuilt engine. The down side to all repairs many of us cannot preform repairs and locked into service shops.We are not mechanics.but before anything happens at repair shop, Contact the DieselClub forum and get some one one advise on direction that may be very helpful moving forward with service repair shops. ask Dave, Dave Atherton Retired Cat Mechanic

Thanks Dave, you were so much help. Anyone that wants to tackle it, it's not that bad. Just took time.Dave is correct, if possible, do your home work. Caterpillar wanted 20K, just to repair my engine the same way I did myself. Even more for a complete reman. engine.

Lastly, when it got down to it, genuine Caterpillar parts were actually comparable in price when shopping. But there are also many NOS Cat parts on Ebay, for 1/4 the price.Import stuff is junk, stay away. Cat parts were packaged nicely, and high quality,always in stock.Something Dave also taught me.

It took awhile to understand Cats parts manual online, but once I did, it was simple. It told you how many of each item you needed, just click on item.I used Western States Caterpillar, they have many stores in the NW.

2 other places I recommend:

Power Machine Service in Spokane Washington did the machine work. Highly recommended

Northwest Diesel parts, was super professional, and gave me a complete written quote for a reman. engine. They are in Portland Oregon. Almost went with them. Complete engine with head and cam $6500.00 (exchange, parts only)

Found many low mile complete engine, of the correct vin# series on the internet for 6-8K delivered with warranty. They were dyno'd and rod's checked.

Several reputable places locally, would have R&R'd the engine for 1-2K. Still a fair deal, less then 10K, with a lower mileage engine.

To be honest, I was unhappy with cat engines when this happened. Probably when I kept hearing "It's a throw away motor". That is because it doesn't have cylinder liners, not a bad thing, just makes it harder to repair in chassis.After dealing with my Cat dealer, and seeing the engine inside, I realize it is well designed, and built with quality parts with great support behind it.Not something I wanted to do, but we now have a new engine.Chris

gracerace, one thing you mention in your post that you touched on that I feel shouldbe expanded upon. The saying ( oh you have one of those throwaway Cat engines.)I been around Caterpillar engines for over 40 years and remember when the 3100 seriescoming into play and schooling with a Diesel engine with out a injection pump or push rods to operate the injectors. The 3100 series engine is a cast block engine with harden steel steel pressed into engine block. This is where the throwaway statement started, howeverlike any rebuild these steel sleeves can be machined out and new ones pressed back in.The cost per cylinder hole is about the same as removal wet sleeve in higher H.P. engines.I find without proper training on the Injection system because of no injection pump or pushrod for injectors or timing marks as in mechanical older engines ( this area where manymechanics are very weak and throw parts at repair,). Caterpillar built this electronic enginelooking ahead that is very popular and trouble free engine for many many miles ahead.Many seem the use of aftermarket parts, aftermarket filters etc. The answer to this is no Use of all OEM parts for the long trouble route to take. The Diesel Club forum has access for all technical information and part numbers for all of the Caterpillar engine used in yourmotorhome today to assist members. Last in closing this term throwaway engine is inoperation everyday still being built and rebuilt. Just ask Caterpillar dealer the cost for exchangefor, failed engine core for rebuild. There is not a Caterpillar engine built that is a throwaway engine. Ask Dave, Dave Atherton Retired Cat Mechanic

Thanks Dave, that is the conclusion I came too, especially after listening to you. As a RV tech (retired) still doing repairs, I find the same thing on house equipment repairs. Techs just throw parts at a problem and charge big bucks.

And as Dave said, buy only Cat parts. I bought a import injector actuator control valve. It wouldn't even let the engine start.I switched with my old one back and forth 3 times, it was bad. It was a year after purchase, so I couldn't return it. Cat part was $250.00. I found a NOS on ebay, still in the box $100.00 delivered.

Same with a Cat block heater,is $130.00 from Cat. Found a NOS one on Ebay, $30.00 delivered. Just do the research.On the other hand, some import stuff is more. Not all Cat parts prices are bad.

I had a customer return from a So. Cal winter trip. His slide was giving him grief. A Mobile RV repair place told him he needed 2 new motors and a harness. $6 K to repair. I spent 3 hours, finding and repairing a pinched wire in the potentiometer part of the harness.At $90.00 an hr, charged him $270.00.

I won't name the company in Spokane publicly, but a dealer I help took a motor home in for a gen set repair (I am not trained on gen set's). They kept it 4 months this summer, all during their selling season. I finally helped them go get it. The company replaced the board (after they said the 1st one was faulty). Then the regulator. It still does not run, they charged them $2100.00 dollars.I knew exactly what happened. They threw parts at it, because they didn't know what they were doing. When it didn't work, they put it aside, so they could make money on something more simple.

My neighbor had a brand name jack fail (not HWH). It was a simple spring inside. Otherwise fine. Can not buy the part. Had to buy a complete new jack. With my dealer discount, it was $900.00.

Same with a slide motor for a customer. A gear broke inside. Can't buy the gear. Tried to have one made. $750.00 my cost for a motor. All it was is a cheap Chinese $50.00 motor and gear.Gave it to them for cost, because I felt bad for them.

I hear this time and time again.So question everything. Overhead for these business's is very high. Employee wages are too. They are forced to charge big bucks, and you end up paying for the tech's training.

Sorry to be negative. Was sharing this to protect you if you are a RV owner and are reading this.

Chris, the going rate to remove engine $ 4,500 to $ 5,000.plus now the same cost to put engine back in motorhome. Add that on top of your first quote or even the amount you spent for partsnot counting your labor. When all this is over and engine running you just put $ 20,000 inyour piggy bank. Ask Dave, Dave Atherton Retired Cat Mechanic